U.S. patent application number 16/852616 was filed with the patent office on 2020-12-03 for treatment of sludges and flocculants using insoluble mineral colloidal suspensions.
This patent application is currently assigned to Heritage Research Group. The applicant listed for this patent is Heritage Research Group. Invention is credited to Perry Eyster, Christopher D. Weber.
Application Number | 20200377401 16/852616 |
Document ID | / |
Family ID | 1000005019541 |
Filed Date | 2020-12-03 |
United States Patent
Application |
20200377401 |
Kind Code |
A1 |
Eyster; Perry ; et
al. |
December 3, 2020 |
TREATMENT OF SLUDGES AND FLOCCULANTS USING INSOLUBLE MINERAL
COLLOIDAL SUSPENSIONS
Abstract
A method of separating sludges which involves adding an
insoluble mineral colloidal suspension into an industrial sludge to
destabilize the industrial sludge and separating destabilized
components of the industrial sludge. The insoluble mineral
colloidal suspension can be adding into the industrial sludge or
formed in situ therein by components into the industrial sludge
that react together therein to form the insoluble mineral colloidal
suspension.
Inventors: |
Eyster; Perry; (Brownsburg,
IN) ; Weber; Christopher D.; (Greenwood, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Heritage Research Group |
Indianapolis |
IN |
US |
|
|
Assignee: |
Heritage Research Group
Indianapolis
IN
|
Family ID: |
1000005019541 |
Appl. No.: |
16/852616 |
Filed: |
April 20, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15715984 |
Sep 26, 2017 |
10662103 |
|
|
16852616 |
|
|
|
|
62399899 |
Sep 26, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F 11/143 20190101;
C02F 11/127 20130101; B01D 21/262 20130101; C02F 11/148 20190101;
B01D 21/01 20130101; C02F 1/5236 20130101; C02F 11/121 20130101;
C02F 1/24 20130101; C02F 11/145 20190101; C02F 11/14 20130101; C02F
1/38 20130101 |
International
Class: |
C02F 11/14 20060101
C02F011/14; C02F 11/127 20060101 C02F011/127; C02F 11/143 20060101
C02F011/143; C02F 11/145 20060101 C02F011/145; B01D 21/26 20060101
B01D021/26; C02F 1/38 20060101 C02F001/38; C02F 1/52 20060101
C02F001/52 |
Claims
1. A method of separating sludges which comprises: obtaining an
industrial sludge, wherein the industrial sludge comprises
wastewater sludge, refinery sludge, sludge from DNF processes,
sludge from DAF processes, sludge from API separators, or tank
clean-out sludge; adding an insoluble mineral colloidal suspension
into the industrial sludge to destabilize the industrial sludge;
and separating destabilized components of the industrial
sludge.
2. A method of separating sludges according to claim 1, wherein a
flocculant and/or coagulant is added to the industrial sludge to
aid in the separation of the destabilized components of the
industrial sludge.
3. A method of separating sludges according to claim 1, wherein the
insoluble mineral colloidal suspension is added into the industrial
sludge by forming the insoluble mineral colloidal in situ in the
industrial sludge.
4. (canceled)
5. (canceled)
6. A method of separating sludges according to claim 1, wherein the
industrial sludge is a combined bottom sludge and top float.
7. A method of separating sludges according to claim 1, wherein the
insoluble mineral colloidal suspension is formed in situ in the
industrial sludge by adding components into the industrial sludge
that react together therein to form the insoluble mineral colloidal
suspension.
8. A method of separating sludges according to claim 1, wherein the
insoluble mineral colloidal suspension has a solids percent by
weight of at least 25%.
9. A method of separating sludges according to claim 8, wherein the
insoluble mineral colloidal suspension has a solids percent of up
to 65%.
10. A method of separating sludges according to claim 9, wherein
the insoluble mineral colloidal suspension has a solids percent by
weight that ranges from 25% to 65%.
11. A method of separating sludges according to claim 1, wherein
the insoluble mineral colloidal suspension comprises an alkaline
earth salt.
12. A method of separating sludges according to claim 11, wherein
the insoluble mineral colloidal suspension comprises a calcium
salt.
13. A method of separating sludges according to claim 1, wherein
the insoluble mineral colloidal suspension comprises an iron
hydroxide.
14. A method of separating sludges according to claim 1, wherein
the insoluble mineral colloidal suspension comprises insoluble
precipitates from a lime softening water treatment process.
15. A process for physically separating components of a sludge
wherein the sludge comprises wastewater sludge, refinery sludge,
sludge from DNF processes, sludge from DAF processes, sludge from
API separators, or tank clean-out sludge, the improvement
comprising adding insoluble mineral colloidal suspension into the
sludge prior to physically separating components of the sludge.
16. A process for physically separating components of a sludge
according to claim 15, wherein the process for physically
separating the components of the sludge includes at least one of
gas-assisted flotation, gravity separation and centrifugal
separation.
17. A process for physically separating components of a sludge
according to claim 16, wherein the process for physically
separating the components of the sludge comprises one of dissolved
nitrogen floatation and dissolved air flotation.
18. A process for physically separating components of a sludge
according to claim 16, wherein the process for physically
separating the components of the sludge comprises the use of an
American Petroleum Institute Separator.
19. A process for physically separating components of a sludge
according to claim 9, wherein the insoluble mineral colloidal
suspension has a solids percent by weight of at least 25%.
20. A process for physically separating components of a sludge
according to claim 9, wherein the insoluble mineral colloidal
suspension has a solids percent of up to 65%.
21. A method of separating sludges according to claim 1, the method
further comprising heating the industrial sludge and insoluble
mineral colloidal suspension to 170.degree. F.
22. The method of separating sludges according to claim 21, wherein
the industrial sludge and insoluble mineral colloidal suspension
are heated from ambient temperature to 170.degree. F.
23. A method of separating sludges according to claim 1, the method
further comprising addition of sulfuric acid to the industrial
sludge and insoluble mineral colloidal suspension to adjust pH to
7-11.
24. A method of separating sludges according to claim 1, the method
further comprising adjusting the pH of the insoluble mineral
colloidal suspension to 7-11 prior to adding the insoluble mineral
colloidal suspension into the industrial sludge.
Description
RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 15/715,984 filed Sep. 26, 2017, which is based upon U.S.
Provisional Application Ser. No. 62/399,899, filed Sep. 26, 2016 to
each of which priority is claimed under 35 U.S.C. .sctn. 120 and of
which the entire specification is hereby expressly incorporated by
reference.
BACKGROUND
[0002] The present invention relates generally to separating
sludges and more particularly to the use of insoluble mineral
colloidal suspensions that can be added to or formed in situ in
sludges and/or floats to aid in separation.
[0003] The wastewater produced from different kinds of industries
normally contains very fine suspended solids, dissolved solids,
inorganic and organic particles, metals and other impurities. Due
to very small size of the particles and presence of surface charge,
the task to bring these particles closer to make heavier mass for
settling and filtration becomes challenging.
[0004] Petroleum refining generates large volumes of oily
wastewater. With industrial development, there is increase in the
amount of oil used. Oil refining, oil storage, transportation and
petrochemical industries in the production process generate a lot
of oily wastewater.
[0005] Separating sludge increases recycled content, reduces the
overall volume of waste generated as well as increases the outlets
available for disposal. Industrial wastewater sludges are often
difficult to separate due to relative density of the components as
well as particle size and charge distribution. For example,
refinery sludge is becoming increasingly difficult to process as
the inorganic content of the crude slate increases. Various
processes throughout refineries increase both the organic content
in the form of polymer flocculants and the inorganic content
captured by the flocculants.
[0006] The low density of particulates in the sludge combined with
the low density of the accumulated spent flocculants and the
increased density of the water component, with high dissolved
solids, results in poor separation.
[0007] Various traditional and advanced technologies have been
utilized to remove the colloidal particles from wastewater; such as
ion exchange, membrane filtration, precipitation, flotation,
solvent extraction, adsorption, coagulation, flocculation,
biological and electrolytic methods.
[0008] Traditional approaches include the addition of bentonite,
lime, ferric compounds, or varying combinations of expensive
coagulants and flocculants. These are often ineffective or require
significant dosing rates.
[0009] Petroleum refiners use Dissolved Nitrogen Floatation (DNF)
units for clarifying wastewater from a variety of refining
processes that include washing from a desalter and other wastewater
generated processes within a refinery.
[0010] DNF units force nitrogen under pressure in the form of
microscopic bubbles often with a coagulant additive to float
particulate matter that has densities near that of water to the top
of the unit where they are skimmed off. Solids that are higher in
density sink to the bottom where they are collected separately. The
middle phase which is absent of solids is sent to wastewater
treatment for processing before discharge.
[0011] The DNF bottom sludge and top float are often combined for
further treatment. According to one aspect the present invention
relates to processing of the combined DNF sludge and float.
[0012] Coagulation is the destabilization of colloidal particles
brought about by the addition of a chemical reagent known as a
coagulant. Flocculation is the agglomeration of destabilized
particles into microfloc, and later into bulky floccules which can
be settled called floc.
[0013] Coagulation is the process by which colloidal particles and
very fine solid suspensions initially present in a wastewater
stream are combined into larger agglomerates that can be separated
by means of sedimentation, flocculation, filtration,
centrifugation, or other separatory methods. This involves a
chemical process in which destabilization of non-settleable
particles is realized. These non-settleable particles can include
most colloids as well as extremely small solid particles and all
solvated (dissolved) particles. These particles form clumps with
the help of a coagulant. Coagulation is commonly achieved by adding
different types of chemicals (coagulants) to the wastewater stream
to promote destabilization of any colloid dispersion present and
the agglomeration of the individual resultant colloidal particles.
Coagulation is the destabilization of these colloids by
neutralizing the electrostatic forces that keep them apart.
Cationic coagulants provide positive electrostatic charges to
reduce the negative electrostatic charges (zeta potential) of the
colloids. As a result, these particles collide to form these larger
floc particles.
[0014] Flocculation refers to the coming together of particles by
means of a physical or mechanical process resulting in the joining
together of large aggregated clumps (or flocs) to form larger
masses and eventually to precipitate them from the liquid phase and
thereby convert them into the solid phase for further separation.
In coagulation, these forces responsible for keeping the particles
suspended and dispersed after they contact each other are reduced.
This is usually referred to as collapsing the colloid and/or
precipitate formation in the case of solvated particles.
Flocculation joins these de-established colloidal dispersions into
large aggregates that enter the solid phase.
[0015] According to the present invention the addition or in situ
formation of insoluble mineral colloidal suspensions in DNF sludges
and floats is used to destabilize DNF sludge and/or float wastes
for purposes of separation and component recovery. Further, these
materials have improved separation in DNF, Dissolved Air Flotation
(DAF), and American Petroleum Institute Separator (API Separator),
and tank clean-out sludges.
BRIEF SUMMARY
[0016] According to various features, characteristics and
embodiments of the present invention which will become apparent as
the description thereof proceeds, the present invention provides a
method of separating sludges which comprises: [0017] obtaining an
industrial sludge; [0018] adding an insoluble mineral colloidal
suspension into the industrial sludge to destabilize the industrial
sludge; and [0019] separating destabilized components of the
industrial sludge.
[0020] The present invention further provides an improvement in
processes for physically separating components of a sludge which
improvement comprises adding insoluble mineral colloidal suspension
into the sludge prior to physically separating components of the
sludge.
DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED
EMBODIMENTS
[0021] The present invention relates generally to separating
sludges and more particularly to the addition of insoluble mineral
colloidal suspensions to DNF, DAF, and API sludges, and other
sludge wastes for purposes of separation and component
recovery.
[0022] The insoluble colloidal mineral suspension used in the
present invention can be added to the sludges and/or floats or can
be generated in situ by forming the insoluble colloidal mineral
suspension from a multi-component mixture that is added to the
sludges and reacts to produce the insoluble mineral colloidal
suspensions in situ. In further embodiments of the present
invention certain waste streams yielding precipitated suspensions
of insoluble minerals have also proven effective. For example, the
slurry formed by concentrating the solids from lime softening of
hard water results in a suspension suitable for use in the
disclosed invention. Those familiar with the art will understand
the benefits of using these materials to destabilize various types
of sludge including DNF, DAF, API, and other sludge and/or float
wastes.
[0023] Adding an insoluble colloidal mineral suspension into an
industrial sludge directly or forming the insoluble colloidal
mineral suspension in situ in an industrial sludge according to the
present invention causes colloidal particles and very fine solid
suspensions initially present in the industrial sludge to combine
into larger agglomerates that can be separated by means of
sedimentation, flocculation, filtration, centrifugation, or other
separatory methods.
[0024] The insoluble colloidal mineral suspensions of the present
invention can include alkaline earth salt precipitates such as
calcium sulfate and barium sulfate which can be added into an
industrial sludge or formed therein by reacting alkaline earth
metals with sulfuric acid to form the corresponding salts.
[0025] In other embodiments a source of iron such as ferric
chloride or ferrous chloride are reacted with hydroxide ions (from
a soluble alkali hydroxide or alkaline hydroxide) to form insoluble
iron hydroxides.
[0026] In further embodiments soluble salts such as calcium
chloride and be reacted with sulfates or carbonates such as
magnesium or sodium sulfate or sodium carbonate to form insoluble
calcium salts including calcium sulfate and calcium carbonate.
[0027] The insoluble colloidal mineral suspensions can have percent
solids deemed sufficient to allow material management, such as
pumpability, but not so low as to burden the system with
unnecessary additional water. Typically, 25-60% solids by weight is
generally suitable for purposes of the present invention. For
insoluble mineral suspension that are formed in situ a comparative
solids percentage by weight can be achieved by factoring in the
solids percent of the components that are combined to form the
resulting insoluble mineral suspension. The concentration of
soluble salts should be below the maximum solubility for the
operating condition for a selected salt and sufficiently high
enough in concentration as to not burden the system with
unnecessary additional water.
[0028] Examples of a waste streams that includes precipitated
suspensions of insoluble minerals which can be used as an insoluble
colloidal mineral suspending according to the present invention
includes slurries made from solids recovered from lime-softening of
boiler water and/or cooling tower water.
[0029] While the insoluble colloidal mineral suspension used
according to the present invention causes colloidal particles and
very fine solid suspensions initially present in an industrial
sludge to combine into larger agglomerates, it can be understood
that the addition of other known coagulants and/or flocculants can
also be used to aid and improved agglomeration and clumping for
separation purposes
[0030] According to the present invention exemplary sludges include
industrial wastewater sludges in general, refinery sludges and in
particular sludges from processes such as DNF, DAF, API separators,
and tank clean-out sludges.
[0031] For purposes of the present invention conventional
flocculants/coagulants can also be used including mineral, natural
and synthetic materials as well as those listed above.
EXAMPLES
[0032] The following non-limited Examples are provided to
illustrate various features and characteristics of the present
invention which are not intended to be specifically limited
thereto.
Example 1
[0033] In this example DNF sludge and float were transferred from a
DNF tank to a smaller tank where a 50-60% solids by weight
suspension of calcium sulfate or barium sulfate in water was added
at 1.5%-2.5% by volume of the DNF sludge and float. A coagulant
(water soluble polymer) was added at 100 to 1000 parts per million
to aid in separation. The combined mixture was heated from ambient
temperature to 170.degree. F. The heated material was then fed to a
three phase centrifuge to separate clean water (centrate), oils and
solids. The centrate had the characteristic of having less than 1%
particulate solids and could be sent back (recovered and recycled)
to the DNF or sent on to wastewater treatment. The oil could be
recovered (and recycled) and the solids could be disposed of.
Example 2
[0034] In this example the same procedure in Examples 1 above was
followed expect a calcium hydroxide slurry was fed into the DNF
sludge and float followed by the addition of sulfuric acid to
adjust pH suitable for polymer activity (pH 7-11). Alternatively
the pH of the calcium hydroxide slurry can be adjusted just prior
to introduction into the sludge or through the proper blending of
calcium hydroxide and calcium sulfate to yield the same effective
pH.
Example 3
[0035] In this example the same procedure of Example 1 and 2 above
was followed except ferric chloride (an alternatively ferrous
chloride) was introduced into the DNF slurry and float together
with soluble alkali/alkaline hydroxide to adjust pH to form
insoluble iron hydroxides.
Example 4
[0036] In this example the same procedure of Examples 1-3 above was
following except soluble salts such as calcium chloride were
introduced into the DNF slurry and float, followed alternatively by
magnesium sulfate, sodium sulfate, or sodium carbonate, to yield
the respective, insoluble calcium salts, calcium sulfate or calcium
carbonate which were all proven to be effective for purposes of the
present invention.
Example 5
[0037] In this example the same procedure of Example 1 above was
followed except solids recovered from lime-softening of boiler
water and cooling tower water was made into a slurry or
alternatively recovered as a slurry, and introduced into the DNF
sludge prior to separation. A 40% solution prepared from
lime-softening solids was added at 1.5% by volume of the DNF sludge
and float.
[0038] Although the present invention has been described with
reference to particular means, materials and embodiments, from the
foregoing description, one skilled in the art can easily ascertain
the essential characteristics of the present invention and various
changes and modifications can be made to adapt the various uses and
characteristics without departing from the spirit and scope of the
present invention as described above and set forth in the attached
claims.
* * * * *